Time-Resolved Pump–Probe Measurement of Optical Rotatory Dispersion in Chiral Metamaterial

Jae Heun Woo, Boyoung Kang, Minji Gwon, Ji Hye Lee, Dong Wook Kim, William Jo, Dong Ho Kim, Jeong Weon Wu

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


A plasmonic chiral metamaterial is fabricated from a thin Au film and exhibits static optical rotatory power (ORP) in the visible spectral range. Transient ORP is measured to clarify the temporal development of ORP using a circularly polarized light (CPL) pump beam. Three distinct transient behaviors of ORP are identified, resulting from different energy relaxation processes of hot electrons that occur during a period of a few picoseconds after pumping. Nonthermal hot electrons experience Lorentz force from an inverse Faraday effect and electron–boundary scattering, yielding a pump beam CPL helicity-dependent transient ORP. Once hot electrons are in thermal equilibrium with the lattice, electron energy is distributed among the occupied states, as described by Fermi–Dirac statistics. Moreover, the transient ORP is independent of pump beam CPL helicity, well explained by the selection rule of electron excitation and two-temperature model of the electron cooling process. Theoretical analysis of the transient ORP in terms of the energy relaxation of thermal hot electrons is carried out by introducing a temperature-dependent dielectric function and finite-difference time-domain simulation. It is found that the magnitude of ORP at an elevated temperature is reduced to less than that at room temperature, agreeing well with the experimental observation.

Original languageEnglish
Article number1700141
JournalAdvanced Optical Materials
Issue number15
StatePublished - 2 Aug 2017

Bibliographical note

Funding Information:
J.H.W. and B.K. contributed equally to this work. This work was carried out in the framework of CNRS International Associated Laboratory Functional Nanostructures: Morphology, Nanoelectronics, and Ultrafast Optics (LIA NANOFUNC) and is supported by the Center for Advanced Meta-Materials (CAMM), funded by the Ministry of Science, ICT, and Future Planning as a Global Frontier Project (2014M3A6B3063700). J.W.W. acknowledges the support from the Ministry of Science, ICT, and Future Planning, Korea (2015001948 and 2014M3A6B3063706). The authors are also grateful to Dr. M. Vomir, Dr. M. Barthelemy, and Dr. J.-Y. Bigot at IPCMS, University of Strasbourg, France, for their contributions in helping the femtosecond pump–probe measurement in this study.

Publisher Copyright:
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


  • chirality
  • hot electrons
  • metamaterials
  • plasmonics
  • time-resolved pump–probe measurement


Dive into the research topics of 'Time-Resolved Pump–Probe Measurement of Optical Rotatory Dispersion in Chiral Metamaterial'. Together they form a unique fingerprint.

Cite this